It has become common practice to wrap elongated articles, such as rolls of floor carpet, in a film of thermoplastic and to heat-seal the wrapping around the article. A water-impervious jacket is thus provided around the article and this is very desirable. An example of an apparatus for performing this packaging function is shown in the patent of Davidson et al. U.S. Pat. No. 3,518,806 which issued July 7, 1970; in this prior art apparatus two rolls of thermoplastic film are mounted in a frame in spaced parallel relationship and the ends of the film are heat-sealed together. The joint is laid along the roll of carpet and the strips from the two rolls are wrapped around in opposite directions until they meet on the opposite side of the roll of carpet. At that point they are heat-sealed to form another sealed joint. The prior art apparatus of this type is complex and expensive and it is very difficult to manipulate heavy articles through the wrapping cycle. When the material emerges from two rolls in the manner described above, the envelope around the wrapped article has two longitudinal seams, which means that the probability of an opening into the envelope occurring is doubled and the appearance of the envelope is somehwat less desirable. Furthermore, if a number of articles of differing lengths are wrapped in this apparatus, the width of plastic film that is used must be selected for the longest article, so that when short articles are wrapped, there is a substantial waste of plastic film. These and other difficulties experienced with the prior art devices have been obviated in a novel manner by the present invention.
An object of this invention is the provision of a packaging machine for elongated articles in which articles of substantially different lengths can be wrapped in the machine without changing rolls of wrapping material and without wasting wrapping material when short length articles are wrapped.
A further object of the present invention is the provision of a packaging machine making use of a plurality of rolls of relatively narrow width thermoplastic film, wherein sub-multiples of these strips can be used to approximate the length of a particular article to be wrapped.
It is another object of the instant invention to provide a packaging machine providing a curtain of multiple strips slightly overlapped and adapted to be heat-sealed when wrapped around an elongated article, means being provided to assure that a given strip is not pulled down from its roll when it is not to be used in wrapping a particular article.
A still further object of the invention is the provision of a packaging machine for wrapping and sealing elongated articles with thermoplastic film, wherein the joint resulting from one wrapping cycle does not appear in the wrapping cycle which immediately follows.
It is a further object of the invention to provide a machine for wrapping an elongated article in a thermoplatic film, wherein the wrapper is made up of a multitude of narrow strips arranged in side-by-side relationship, the article and wrapping being subjected to a heat-shrinking operation after the wrapping is completed.
It is a still further object of the present invention to provide a packaging machine for elongated articles, which machine is rugged in construction, which is inexpensive to manufacture, which can be operated by unskilled labor, or be built in full-automatic version, and which is capable of a long life of useful service with a minimum of maintenance.
It is another object of the invention to provide a packaging machine which can wrap objects longer than the width of the widest plastic films commercially available, through the device of a segmented film curtain made up of segments of film of width which are commercially available.
With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.